That socket, measuring roughly nine centimetres by six and only five centimetres deep, with gently sloping sides, is what remains of a cross base, the foot of a shaft that has long since disappeared. The block itself tapers slightly as it rises, from twenty-two centimetres wide at the base to seventeen at the top, and stands just thirty-four centimetres high. It is an unassuming object, easy to overlook, but it is evidence of a once-standing cross whose presence marked sacred ground on one of the most significant early medieval island monasteries in Ireland.

The stone was first recorded by R. A. S. Macalister, the archaeologist and epigrapher, in a 1916 to 1917 publication, at which point it was still positioned at the southern wall of the nave of St. Caimin's church. St. Caimin was a seventh-century monk associated with the founding of the monastic settlement on Inis Cealtra, and his church remains one of several ecclesiastical structures clustered on the island. At some point after Macalister's observation, the cross base was moved indoors for safekeeping. The material, sandstone, is relatively soft and vulnerable to weathering, which may explain the decision to bring it under shelter rather than leave it in situ against the church wall where he had found it.